Start with a lightweight block‑design: choose a small, high‑strength material like titanium for the crankcase to reduce weight. Next, lay out a short stroke, long‑stroke ratio so the piston travels a shorter distance but maintains compression. Keep the bore small to raise RPM potential but fit a larger cam profile that lifts the valves at higher speeds. Add a dual‑jet throttle system so the airflow is finely controlled. Install a variable‑geometry turbo that expands at low RPM for torque but narrows as RPM climbs to limit boost. Use a high‑efficiency intercooler to keep intake temperatures low. Balance the crank and flywheel carefully—an oversized flywheel adds torque but lowers revs, so keep it moderate. Fit a lightweight, high‑strength connecting rod with a larger pin to reduce flex. Finally, tune the ECU with a custom map that ramps boost slowly, keeping peak pressure below the engine’s red line, and test with a dyno to adjust for optimal torque.

You’re right about the plugs – go for a high‑heat ceramic insert that can handle the boost pressure without hopping. After the first dyno run, check the rev‑range map and bump the cam lift by a millimetre or so; that gives the engine a little breathing room before it spikes. For the exhaust, aim for a tapered pipe that keeps back pressure in the 0.5‑0.8 psi range; that smooths the torque curve and keeps the throttle response tidy. Keep tweaking, and you’ll have a compact engine that revs high yet delivers plenty of punch.